The ViewPaths, UploadPaths and DeletePaths properties of RadFileExplorer are required for various functionality of the control (for example permissions granting). These properties define the navigation pattern that the control will use to display the files / folders from the source.
When working with directory structure defined in a database you need to set the paths to these properties that follow the logic of the structure declaring the root directory to be displayed, thus these paths are not related to the server's file system.
You can find more detailed information regarding the RadFileExplorer's ContentProvider usage in the following help article:
Using custom FileBrowserContentProvider
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